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Mar 30, 2023

Healthy Aging


Using Varenicline to Quit Smoking

What Is Varenicline?

Varenicline is the only medication approved by the FDA exclusively for the use of smoking cessation. It is not the first-line medication when you try to quit smoking. It's typically reserved for people who have tried but have not been successful. However, it's the most effective medication to be used in isolation, as compared to any other smoking cessation aid.

Health Risks of Smoking

Smoking is the number one cause of preventable death in the United States. Cigarettes contain chemicals such as formaldehyde and arsenic, making them known carcinogens (causing cancer) and direct contributors to other health conditions like chronic obstructive pulmonary disease (COPD). The health risks are so well known and yet people continue smoking because it’s extremely difficult to quit once you’ve started. Quitting smoking is tough due to both the addictive nature of nicotine as well as the uncomfortable withdrawal symptoms that come with quitting. That is why there are programs that help people to quit smoking. These programs include lifestyle tips, and importantly, certain medications that can help you to decrease your cravings and withdrawal symptoms.

Learn more about smoking cessation

How Varenicline Works

Varenicline works differently from other smoking cessation aids. It has two main mechanisms:

  • Working on a receptor in the same way as nicotine — gives you some benefit of the desired nicotine effect
  • Preventing nicotine from binding to the receptor — smoking doesn’t give you the same effect you seek

This stops your cravings to smoke when smoking doesn’t give you the same effect you typically desire. This helps to both stop your smoking cravings and reduce your withdrawal symptoms with some of that similar effect of nicotine.

Varenicline is a great second-line therapy for smoking cessation. The first-line options are nicotine replacement therapy (NRT) and bupropion. Varenicline is different in that it’s typically not recommended to take in combination with NRT. While it is common to combine different forms of NRT and even other smoking cessation medications (such as bupropion) with NRT, it has not been shown to be efficacious to combine NRT with varenicline. In fact, combining the two actually leads to more people going back to smoking to avoid the side effects of the combination (such as nausea, headache, and dizziness).

Taking Varenicline

Varenicline is usually recommended to be taken in combination with counseling or other external support systems for the best effect.

Varenicline therapy must be started at least 1 week before your smoking quit date. This gives the medication time to take effect before you stop smoking so it can have the greatest benefit. This week also allows you to titrate the dose up. Typically, varenicline dosage starts with 0.5 mg once in the morning for 3 days, then 0.5 mg twice daily for 4 days, and then 1 mg twice daily for the remainder of therapy. Therapy with varenicline is typically 12 weeks, but it is important to take the medication exactly as directed by your healthcare provider for exactly as long as they direct.

It is also very important to take your varenicline after eating a meal and with a full glass of water.

Varenicline Side Effects

The main adverse reactions known to be experienced with smoking cessation are the smoking withdrawal symptoms rather than adverse reactions from a medication. These symptoms include irritability, anxiety, increased appetite/weight gain, difficulty sleeping, etc. However, these symptoms will typically peak after 2-3 days and generally resolve completely by 2 weeks.

Varenicline itself has also been associated with some unwanted side effects. The most common experienced include:

  • Nausea/vomiting
  • Sleep difficulty
  • Constipation
  • Flatulence
  • Psychiatric symptoms

*there have been some reports of the emergence of psychiatric symptoms (such as mania, mood swings, depression, or even suicidal thoughts) in those starting varenicline. Speak with your healthcare provider immediately if you notice your mood change when taking varenicline.

It is important to speak with your healthcare provider about any side effects that you may be experiencing while taking varenicline, instead of just discontinuing the medication due to the effects. They will help determine if it is still worth taking the medication or if another medication may be right for you.

Be Cautious When Taking Varenicline If You:

Have Kidney Impairment

Dosage adjustment may be required in those with kidney impairment, as the medication may reach high enough levels to be toxic in these individuals.

Are Pregnant

This medication may have negative effects on a growing fetus when taken by pregnant individuals. It is therefore generally recommended to avoid taking this medication while pregnant, unless otherwise advised by a healthcare professional.

Are Breastfeeding

Varenicline is transferred into the breastmilk from animals taking the medication. It has not been studied in humans, but due to the potential risk of transfer and additional risk to the infant, it’s recommended to avoid varenicline use in breastfeeding individuals.

If you are thinking about quitting smoking, speak with your healthcare provider about options to make this transition easier for you. It is never too late to quit smoking!


  1. Chantix (varenicline) – Access data FDA-Approved Drugs [Internet]. [Amended 07/2009; accessed 09/2022].
  2. e-CPS: The Compendium of Pharmaceuticals and Specialties: The Canadian Drug Reference for Health Professionals (https://www-e-therapeutics-ca). Accessed 2022-09-02.
  3. Lexicomp: Evidence-Based Drug Information ( Accessed 2022-09-02.
  4. Pharmacologic Product Guide: FDA-Approved Medications for Smoking Cessation. (2022). Retrieved 06 September 2022, from
  5. What are the health risks of smoking?. (2022). Retrieved 6 September 2022, from

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